The Role Of Polarity Protein Scrib On Chick Gastrula

Organogenesis and Differentiation initially occur in gastrula during embryo development. Blastula epiblast cells migrate to midline of embryo and undergo EMT to transit mesoderm in primitive streak. And then neural tube, somite, cardiac, brain, archenteron, vascular formed simitanously or in the follwoing. Many factors and genes were repoted to be involved in affecting cell migration in oogenesis and subsequent development, in which polarity genes are of importance in this process. The polarity protein Scrib is a scaffolding protein belonging to lap protein family. Knocking out scrib caused epithelial cells to lose apical-based polarity and abnormal cell cycle in drosophila. Human Scrib has been identified as a tumor suppressor gene. And scrib also play an important role in maintaining synapses function and internal ear development. Our laboratory previous research revealed that scrib can bind numb to negatively regulate notch signal in vitro experiments. But it unclear whether this signal play role on organism development. This subject aimed at overexpression of Scrib and numb gene to determine if early embryo develop normally or not in vivo using chick embryo model.We detected Scrib, Numb mRNAs expression in normal chick embryo by in situ hybridization. Scrib mainly express in anterior primitive streak during HH 4 embryo, and the expression is dispersed in HH7 along with embryo devlopment. Using the same experimental strategy, we obtained the uniform data in numb mRNA expression. After overexpressing scrib and numb by electroporation in HH 3-4 stages embryo, we found that the ability of sheet-like epiblast cells through EMT was inhibited in early gastrulation and postponed/deformed neurulation in later gastrulation. And we knock down Scrib which can promote neural tube development. Meanwhile we assessed some related proteins expression with neural development after manipulating gene expression level of Scrib or numb, and demonstrated that there was no effect on Pax-7 expression but inhibited expression of Islet-1.ConclusionScrib and numb genes are probably important in modulating chick development during gastrulation, in which more specifically scrib and numb could inhibit EMT process and neural tube closure during neurulation.